723. Immunogenicity and Duration of Protection Among Hemodialysis Patients After Primary or Revaccination Series of Hepatitis B Vaccine: Implications for Defining Vaccine-Induced Immunity
Session: Poster Abstract Session: Vaccine Studies, Adjuvants, and Discovery
Friday, October 21, 2011
Room: Poster Hall B1
Background: Hepatitis B vaccination is recommended for patients on hemodialysis, however, seroprotection after a primary vaccine series is suboptimum. Limited data are available on the effect of revaccination of non-responders and on persistence of immunity in this population with currently approved regimens.

Methods: Hepatitis B vaccine (40 µg/dose) was given to 77 susceptible patients on hemodialysis (0, 1, and 6 month schedule). Levels of hepatitis B surface antibody (anti-HBs) were tested >28 days after the third dose was administered, and non-responders revaccinated with an additional 3-dose series. Vaccine responders (anti-HBs ≥10 mIU/mL) were re-tested every 6 months and booster doses given as needed. Kaplan-Meier survival curve was used to estimate the probability of maintaining protective antibody level.  Cox-proportional hazards model was used to assess the association between time to loss of protective antibody levels and certain explanatory variables.

Results: Overall vaccine-induced response was 79.2% (95% CI 68.2%, 87.3%). Among weak responders, protective antibody levels persisted in 44% for 12 months post-vaccination; whereas among strong responders (anti-HBs level ≥100 mIU/mL), protective antibody levels persisted in 92% for 12 months, and 68% for 24 months post-vaccination. A weak post-vaccination response (anti-HBs level 10.0-99.9 mIU/mL) increased the risk of losing protective antibody levels (adjusted hazard ratio, 9.7; 95% confidence interval, 3.5-28.5; p<0.0001).

Conclusion: Revaccinating patients undergoing hemodialysis who do not respond to a primary vaccine series substantially increases the pool of protected patients. The threshold for defining hepatitis B vaccine-induced immunity should be revisited in this patient population to maximize the duration of protection.


Subject Category: I. Adult and Pediatric Vaccines

Sandra Chaves, MD, MSc1, Danni Daniels, MS1, Brian Cooper, MD2, Susan Malo-Schlegel, RN CIC2, Susan MacArthur, RN CIC CPHQ MPH3, John Kobetitsch, R.N. J.D.2, Aimee McDanial, MSN RN2, John D'Avella, MD FASN2 and Miriam J Alter, PhD4, (1)Centers for Disease Control and Prevention, Atlanta, GA, (2)Hartford Hospital, Hartford, CT, (3)Connecticut Childrens Medical Center, Hartford, CT, (4)University of Texas Medical Branch, Galveston, TX

Disclosures:

S. Chaves, None

D. Daniels, None

B. Cooper, None

S. Malo-Schlegel, None

S. MacArthur, None

J. Kobetitsch, None

A. McDanial, None

J. D'Avella, None

M. J. Alter, None

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